I do some contract work for a small Internet Cafe near my old hometown. As of now, I'm sitting in the back hiding from customers, trying to bring the client machines back up to some kind of useful state.
As you might guess, malware is a huge problem in an internet cafe with windows based client machines. So most of my current headache stems from trying to extract wriggling badness from the soft flesh of Windows 98.
At the Cafe, they've been using NAV: corporate for AV, but that's it. So I've installed ad-aware and spybot. Spybot caught some things that AAW missed, but there's no harm in having both of them. For kicks, I installed AVG as well. AVG caught some viruses that Norton missed.
The traditional wisdom is that Norton is top of the line, and if you've got cash to drop, drop it there. So I'm very surprised to find that AVG (traditionally described as an underdog that is only popular because of their free edition) outperforms NAV sometimes. And yes, before someone asks, both were updated immediately before the scan.